class Kramdown::Converter::Man

def convert(el, opts = {indent: 0, result: +''}) #:nodoc:
  send("convert_#{el.type}", el, opts)
end

def convert_a(el, opts)
  if el.children.size == 1 && el.children[0].type == :text &&
      el.attr['href'] == el.children[0].value
    newline(opts[:result]) << macro("UR", escape(el.attr['href'])) << macro("UE")
  elsif el.attr['href'].start_with?('mailto:')
    newline(opts[:result]) << macro("MT", escape(el.attr['href'].sub(/^mailto:/, ''))) <<
      macro("UE")
  else
    newline(opts[:result]) << macro("UR", escape(el.attr['href']))
    inner(el, opts)
    newline(opts[:result]) << macro("UE")
  end
end

def convert_abbreviation(el, opts)
  opts[:result] << escape(el.value)
end

def convert_blank(*)
end

def convert_blockquote(el, opts)
  opts[:result] << macro("RS")
  inner(el, opts)
  opts[:result] << macro("RE")
end

def convert_br(_el, opts)
  newline(opts[:result]) << macro("br")
end

def convert_codeblock(el, opts)
  opts[:result] << macro("sp") << macro("RS", 4) << macro("EX")
  opts[:result] << newline(escape(el.value, true))
  opts[:result] << macro("EE") << macro("RE")
end

def convert_codespan(el, opts)
  opts[:result] << "\\fB#{escape(el.value)}\\fP"
end

def convert_dd(el, opts)
  inner(el, opts, :first)
  if el.children.size > 1
    opts[:result] << macro("RS")
    inner(el, opts, :rest)
    opts[:result] << macro("RE")
  end
  opts[:result] << macro("sp") if opts[:next] && opts[:next].type == :dd
end

def convert_dt(el, opts)
  opts[:result] << macro(opts[:prev] && opts[:prev].type == :dt ? "TQ" : "TP")
  inner(el, opts)
  opts[:result] << "\n"
end

def convert_em(el, opts)
  opts[:result] << '\fI'
  inner(el, opts)
  opts[:result] << '\fP'
end

def convert_entity(el, opts)
  opts[:result] << unicode_char(el.value.code_point)
end

def convert_footnote(*)
  warning("Footnotes are not supported")
end

def convert_header(el, opts)
  return unless opts[:parent].type == :root
  case el.options[:level]
  when 1
    unless @title_done
      @title_done = true
      data = el.options[:raw_text].scan(/([^(]+)\s*\((\d\w*)\)(?:\s*-+\s*(.*))?/).first ||
        el.options[:raw_text].scan(/([^\s]+)\s*(?:-*\s+)?()(.*)/).first
      return unless data && data[0]
      name = data[0]
      section = (data[1].to_s.empty? ? el.attr['data-section'] || '7' : data[1])
      description = (data[2].to_s.empty? ? nil : " - #{data[2]}")
      date = el.attr['data-date'] ? quote(el.attr['data-date']) : nil
      extra = (el.attr['data-extra'] ? quote(escape(el.attr['data-extra'].to_s)) : nil)
      opts[:result] << macro("TH", quote(escape(name.upcase)), quote(section), date, extra)
      if description
        opts[:result] << macro("SH", "NAME") << escape("#{name}#{description}") << "\n"
      end
    end
  when 2
    opts[:result] << macro("SH", quote(escape(el.options[:raw_text])))
  when 3
    opts[:result] << macro("SS", quote(escape(el.options[:raw_text])))
  else
    warning("Header levels greater than three are not supported")
  end
end

def convert_html_element(*)
  warning("HTML elements are not supported")
end

def convert_img(_el, _opts)
  warning("Images are not supported")
end

def convert_li(el, opts)
  sym = (opts[:parent].type == :ul ? '\(bu' : "#{opts[:index] + 1}.")
  opts[:result] << macro("IP", sym, 4)
  inner(el, opts, :first)
  if el.children.size > 1
    opts[:result] << macro("RS")
    inner(el, opts, :rest)
    opts[:result] << macro("RE")
  end
end

def convert_math(el, opts)
  if el.options[:category] == :block
    convert_codeblock(el, opts)
  else
    convert_codespan(el, opts)
  end
end

def convert_p(el, opts)
  if (opts[:index] != 0 && opts[:prev].type != :header) ||
      (opts[:parent].type == :blockquote && opts[:index] == 0)
    opts[:result] << macro("P")
  end
  inner(el, opts)
  newline(opts[:result])
end

def convert_raw(*)
  warning("Raw content is not supported")
end

def convert_root(el, opts)
  @title_done = false
  opts[:result] = +".\\\" generated by kramdown\n"
  inner(el, opts)
  opts[:result]
end

def convert_smart_quote(el, opts)
  opts[:result] << unicode_char(::Kramdown::Utils::Entities.entity(el.value.to_s).code_point)
end

def convert_strong(el, opts)
  opts[:result] << '\fB'
  inner(el, opts)
  opts[:result] << '\fP'
end

def convert_table(el, opts)
  opts[:alignment] = el.options[:alignment].map {|a| TABLE_CELL_ALIGNMENT[a] }
  table_options = ["box"]
  table_options << "center" if el.attr['class'] =~ /\bcenter\b/
  opts[:result] << macro("TS") << "#{table_options.join(' ')} ;\n"
  inner(el, opts)
  opts[:result] << macro("TE") << macro("sp")
end

def convert_tbody(el, opts)
  opts[:result] << ".T&\n" if opts[:index] != 0
  opts[:result] << opts[:alignment].join(' ') << " .\n"
  inner(el, opts)
  opts[:result] << (opts[:next].type == :tfoot ? "=\n" : "_\n") if opts[:next]
end

def convert_td(el, opts)
  result = opts[:result]
  opts[:result] = +''
  inner(el, opts)
  if opts[:result] =~ /\n/
    warning("Table cells using links are not supported")
    result << "\t"
  else
    result << opts[:result] << "\t"
  end
end

def convert_text(el, opts)
  text = escape(el.value)
  text.lstrip! if opts[:result][-1] == "\n"
  opts[:result] << text
end

def convert_tfoot(el, opts)
  inner(el, opts)
end

def convert_thead(el, opts)
  opts[:result] << opts[:alignment].map {|a| "#{a}b" }.join(' ') << " .\n"
  inner(el, opts)
  opts[:result] << "=\n"
end

def convert_tr(el, opts)
  inner(el, opts)
  opts[:result] << "\n"
end

def convert_typographic_sym(el, opts)
  opts[:result] << TYPOGRAPHIC_SYMS_MAP[el.value]
end

def convert_ul(el, opts)
  compact = (el.attr['class'] =~ /\bcompact\b/)
  opts[:result] << macro("sp") << macro("PD", 0) if compact
  inner(el, opts)
  opts[:result] << macro("PD") if compact
end

def convert_xml_comment(el, opts)
  newline(opts[:result]) << ".\"#{escape(el.value, true).rstrip.gsub(/\n/, "\n.\"")}\n"
end

def escape(text, preserve_whitespace = false)
  text = (preserve_whitespace ? text.dup : text.gsub(/\s+/, ' '))
  text.gsub!('\\', "\\e")
  text.gsub!(/^\./, '\\\\&.')
  text.gsub!(/[.'-]/) {|m| "\\#{m}" }
  text
end

def inner(el, opts, use = :all)
  arr = el.children.reject {|e| e.type == :blank }
  arr.each_with_index do |inner_el, index|
    next if use == :rest && index == 0
    break if use == :first && index > 0
    options = opts.dup
    options[:parent] = el
    options[:index] = index
    options[:prev] = (index == 0 ? nil : arr[index - 1])
    options[:next] = (index == arr.length - 1 ? nil : arr[index + 1])
    convert(inner_el, options)
  end
end

def macro(name, *args)
  ".#{[name, *args].compact.join(' ')}\n"
end

def newline(text)
  text << "\n" unless text[-1] == "\n"
  text
end

def quote(text)
  "\"#{text.gsub(/"/, '\\"')}\""
end

def unicode_char(codepoint)
  "\\[u#{codepoint.to_s(16).rjust(4, '0')}]"
end